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Stages of cancer diagnosis - What they tell you beyond survival rates
Dr Khoo Kei Siong explains how cancer is classified and why it matters
In TNM staging , T describes the size and extent of the main or the primary tumour ; N indicates whether the cancer has spread to the nearby lymph nodes ; while M tells us whether the cancer has spread to other parts of the body ( i . e ., metastasis )
The stage of a cancer refers to the anatomical extent of the cancer .
A staging system typically incorporates some or all of the following aspects of a cancer : the size of the tumour , the extent of invasion of the adjacent tissue or organ , whether the cancer has spread to nearby lymph nodes or different parts of the body , and tumour grade , which refers to how abnormal the cancer cells look .
Around the world , TNM staging is the most commonly used cancer staging system .
How cancer stages are determined - the five stages of cancer TNM staging can be applied to most cancers , with the exception of cancer of the central nervous system ( i . e ., brain and spinal cord tumours ) and blood cancers ( i . e ., lymphoma and leukaemia ).
In TNM staging , T describes the size and extent of the main or the primary tumour ; N indicates whether the cancer has spread to the nearby lymph nodes ; while M tells us whether the cancer has spread to other parts of the body ( i . e ., metastasis ).
TNM staging describes the stage of a cancer in detail . Different TNM stages of similar prognosis are grouped together into five stages of cancer for ease of communication between doctors :
Stage 0 - Cancer that has not yet become invasive ( i . e ., carcinoma-in-situ ). Patients at Stage 0 have excellent prognosis and can often be cured with just surgery alone .
Stage 1 - Almost always a small tumour that is confined to the organ .
Stage 2 - Usually a bigger localised tumour , sometimes with limited involvement of nearby lymph nodes .
Stage 3 - A much larger tumour with more extensive involvement of either the adjacent tissue or lymph nodes , but with no evidence of spread to other parts of the body .
Stage 4 - Cancer that has spread to distant parts of the body .
Clinical staging vs pathological staging The difference between clinical staging and pathological staging lies mainly in the kind of information taken into account during examinations and pathology .
Clinical staging is based on findings of physical examinations , blood tests , radiological imaging ( X-rays , CT scans , MRIs , PET scans , etc .), endoscopy , and any biopsies that are done when the cancer is first diagnosed before any treatment is given . This is a major factor that determines the appropriate treatment option for the patient .
Pathological staging takes into account the findings during surgery and the examination of the tumour specimen by the pathologist in addition to the information gathered from clinical staging . Pathological staging gives additional information for further treatment , such as chemotherapy , hormonal therapy , and radiotherapy .
Beyond survival rates The stage of the cancer allows doctors to estimate the long-term outcome of the cancer , such as its survival . However , staging also helps doctors and patients
68 AUGUST 2021 GlobalHealthAndTravel . com